In recent years, it has become possible to quite easily distribute data in the form of digitized content data such as video images of high quality and audio sounds of high quality with the speeding up of networks and the rapid spread of personal computers and digital television receivers into general households. Further, as even general users have come to be able to easily handle digital content data (hereinafter, “contents”), services of providing various contents have become popular. With the diversification of storage media such as hard disk devices, DVDs (digital versatile discs) and SD (secure digital) memory cards (product name), the capacities of storage media are in the process of becoming larger. Thus, even small-sized storage media such as SD memory cards can store a content which becomes a large-volume data such as a two-hour long movie program, and even general households are coming to possess a huge amount of contents.
As one form of the storage media capable of storing contents, there are semiconductor storage media having built-in semiconductor memories. Further, card-shaped semiconductor memory cards (hereinafter, merely “memory cards”) are known as semiconductor storage media. For example, memory cards are internally provided with semiconductor memories such as flash memories. The memory cards enable the storage and reproduction of contents by permitting video data and sound data to be written in the semiconductor memories and permitting them to be read.
Memory cards include, for example, SD memory cards (product name) mentioned above, memory sticks (product name), smart media (product name), compact flashes (registered trademark) or multimedia cards called MMCs. As compared to DVDs capable of storing a large-volume data, the memory cards are smaller and more compact. For this reason, the memory cards are coming to be used for storing or reproducing contents by being mounted in portable information processing apparatuses such as mobile phones or portable players. Further, personal computers and the like are coming to be provided with interfaces to and from which the memory cards can be attached and detached.
With the capability of mounting the memory cards in various information processing apparatuses and the like in this way, it becomes possible, for example, that one collects various data by means of a mobile phone and stores them in a memory card while being out, and mounts this memory card in a personal computer at home to edit the collected various data. Alternatively, one can store a music data edited using a personal computer in a memory card and mount the memory card in a portable player to reproduce the music data while being out. In this way, various modes of utilization taking advantage of the compactness of the memory card can be thought.
On the other hand, since the memory cards are small-sized and compact as described above, they are often used while being carried around and, hence, it can be predicted that the reproduction and storage of contents are often interrupted. For example, in the case of using a memory card in a portable music player, the frequent use is thought to temporarily interrupting the reproduction of the music data and resume the reproduction of a music data since music is often reproduced while the music player is carried around. Further, since the memory card is easily attachable and detachable to and from an apparatus main body, the attachment and detachment of the memory card to and from the apparatus main body are predicted to be relatively frequent with a power supply kept on. Furthermore, in the case of using a content download service using a mobile phone with a memory card mounted in the mobile phone, a communication interruption occurs when a user goes out of a wireless area or the quality of a radio transmission path is deteriorated, thereby interrupting the downloading. As a result, a problem of stopping the storage of the content halfway can be thought.
Thus, there has been proposed a technology of judging whether or not storage/reproduction can be continued after a data transfer for the storage/reproduction is interrupted in an information processing apparatus capable of storing and/or reproducing data by mounting a memory card mounted thereinto (for example, see Japanese Unexamined Patent Publication No. 2002-288142, hereinafter referred to as patent document 1).
FIG. 13 is a block diagram showing the construction of a prior art communication terminal unit having a resumption judging function for an interrupted data transfer as disclosed in patent document 1. In FIG. 13, a communication terminal unit 99 is provided with a communicator 991, a controller 992, a memory card interface 993, a storage 994 and a user interface 995. Thus, the communication terminal unit 99 receives a data downloaded from a content server 91 via a communication network. The communication terminal unit 99 further stores the received data in a memory card 93 mounted in the memory card interface 993 thereof via the memory card interface 993.
The communicator 991 receives the data downloaded from the content server 91. The user interface 995 functions as an interface for a user. The controller 992 controls the respective parts of the communication terminal unit 99 including the interruption of the storage of the downloaded data, the control of resuming the storage and the processing of downloaded data. The storage 994 saves information used to control the respective parts of the communication terminal unit 99 including information used for controls to interrupt the storage of the downloaded data and resume the storage and information used to process the downloaded data. The memory card interface 993 functions as an interface for the mounted memory card 93.
A terminal ID used to individually distinguish the communication terminal unit 99 is saved in a terminal ID memory area 941 of the storage 994. Every time downloading is made, download identification information used to distinguish the download being executed from other downloads is saved in a download identification information memory area 942 by a download interruption controlling function 921 of the controller 992. The terminal ID and the download identification information are saved in an administration area 931 of the memory card 93.
In the case that a user inputs a download request by way of the user interface 995, the terminal IDs saved in the terminal ID memory area 941 and the administration area 931 and the pieces of the download identification information saved in the download identification information memory area 942 and the administration area 931 are compared by a download resumption judging function 922 of the controller 992. If the memory card 93 contains a data whose downloading was interrupted, the download resumption judging function 922 judges whether or not the downloading of the interrupted data can be resumed based on a comparison result. If it is judged that the downloading can be resumed from an interrupted position as a result of the resumption judgment, the downloading is so resumed as to continue from the interrupted position by the download resumption controlling function 923 of the controller 992, and the data after the interruption is saved in the memory card 93.
By the above construction, the downloading can be resumed only when the same communication terminal unit that was used before the interruption of the downloading is used and the same memory card that was used before the interruption of the downloading was interrupted. This can prevent a problem of saving contents as constituent parts of the same content in a plurality of memory cards in a divided manner.
However, the prior art technology disclosed in patent document 1 has a problem of being able to resume the downloading on a per-content basis. For example, if a data to be downloaded is a music content, the downloading had to be resumed from the starting end of a fifth song when an interruption is made during the downloading of the fifth song upon downloading ten songs together. As described above, SD memory cards are about to obtain a storage capacity sufficient to save a two-hour long movie content at present. If the downloading of such a huge content is interrupted, the downloading has to be resumed by reversing up to two hours.
Since the memory cards are frequently attached to and detached from various apparatuses and devices as described above, causes for interrupting the downloading are thought to include, for example, a contact failure at the time of mounting the memory cards, a contact failure during the storage and/or reproduction, an inadvertent error of turning the power supply off, i.e. entering an off state in addition to the aforementioned causes. If interruptions are often made due to such causes during the downloading of a huge content, the convenience or user-friendliness of the communication terminal unit and the memory card may be impaired.